This invention relates to an ultrasonic system and method for facilitating access of a diagnostic, therapeutic, probing, dilating or manipulating instrument through a body passageway wherein the internal diameter of the body passageway is initially smaller than the external diameter of the instrument. More specifically, this invention relates to an ultrasonic system and method for facilitating dilation of the cervix.
Various surgical devices employing ultrasonic-vibratory means are known in the art. U.S. Pat. No. 4,169,984 discloses an ultrasonic probe for ultrasonically removing material such as in the de-scaling of teeth and pulverizing of cataract tissue. U.S. Pat. No. 4,136,700 discloses an apparatus for use in surgically removing tumorous neurological tissue having a tool tip vibrating in the ultrasonic range, irrigation means and expiration means. U.S. Pat. No. 3,884,239 discloses a tool for use in connection with the introduction of an implant into a mucosa-lined body having a vibrating unit connected with a mucosa-engaging structure for removing a mucosa lining from the interior of the body cavity. U.S. Pat. No. 3,589,363 discloses an instrument having a working operative tip vibrating at high frequencies and with minute amplitudes for breaking apart and removing material such as in the removal of cataracts from the eye.
All of the foregoing references illustrate applications of ultrasound for the purpose of damaging tissue.
An object of the present invention is to provide an ultrasonic system which protects tissue from damage and is uniquely useful for facilitating access of a medical instrument through a body passageway wherein the internal diameter of the body passageway is initially smaller than the external diameter of the instrument.
A further object of the invention is to provide an ultrasonic cervical dilator system using relatively low power as compared to the tissue-destroying illustrations of the prior art, and which is useful for assisting in gentle and tissue-protective dilation of the cervix.
Another object of the invention is to provide an ultrasonic cervical dilator system which generates minimum heat and essentially no tissue injury due to thermal, cavitory or protoplastic streaming effects.
A still further object of the invention is to provide an ultrasonic cervical dilator system which greatly reduces cervical injury which commonly occurs during forcible dilation of the cervix.